Tweaking quail input methods

[Stefan Monnier]

Is there a way for the end-user to tweak a quail input method?

I like to use the TeX input method and could almost live with it being
always enabled, except for some of its mappings which sometimes get in
the way.  So I'd like to either define a new input method derived from
TeX, or to tweak the TeX input method.

The kind of changes I'd like to apply are things like:
- eliminate all mappings that start with a particular prefix
- add a few mappings
- move mapping from prefix <foo> to prefix <bar> (e.g. move all entries
  of the form "_<something>" so they use "\\_<something>" instead).

I looked at quail.el but can't seem to find anything that would let me
do that.


        Stefan